About 697,000 U.S. service men and women served in the 1990–1991 Gulf War which liberated Kuwait from Iraqi forces. A number of health studies, including the VA National Health Survey of Gulf War Era Veterans and Their Families and the Longitudinal Health Study of Gulf War Era Veterans, have identified a constellation of symptoms and health conditions associated with Gulf War deployment including PTSD, MSI, and CFS-like illness. Long-term epidemiologic studies have begun to clarify why some but not all Gulf War veterans developed chronic symptoms as a result of deployment and why MSI, CFS-like illness, and PTSD persist in some subgroups of veterans. Individual variation over time in symptom-based illnesses may be the result of differences in levels of environmental exposures or genetic susceptibility. Although co-morbid conditions may influence the persistence or progression of MSI and CFS-like illness, we did not observe any associations in multivariate analysis between obesity and either MSI or CFS-like illness.
The specific exposures that account for increased risks of MSI and CFS-like illness among Gulf War Veterans are unknown but may include environmental factors such as pyridostigmine bromide or exposure to certain pesticides [23
]. Many of the troops were exposed to a wide array of wartime and environmental exposures including psychological stress, solvents, fuels, and pesticides, pyridostigmine bromide pills given to protect troops from effects of nerve agents, smoke from large numbers of oil well fires, and multiple prophylactic vaccines given to protect against anthrax and other infectious agents. Some troops were also potentially exposed to low-level sarin or other nerve agents as a result of the burning of munitions dumps. Multiple exposures often occurred and the effects of two or more combined exposures (for example, mixtures of respiratory irritants such as oil smoke and fuel combustion products and combinations of neurotoxic substances such as certain pesticides and low-level nerve agents) may have potentiated each other [23
A further issue is that the cohort of Gulf War veterans is advancing in age and these veterans are likely to be at increasing risk of not only certain deployment-related health conditions but also chronic diseases associated with “lifestyle factors” (e.g., physical inactivity and a high caloric or high fat diet). An increasing number of studies have identified overweight and obesity as important health concerns among U.S. veterans of various ages [1
]. Important associations may exist between obesity and adverse health conditions related to service in the Gulf War such as PTSD [10
]. Persons with PTSD or depression may be less likely to remain active or to eat a healthy diet. Dietary information was not collected in the current study. Possible biologic pathways for a link between PTSD and obesity may involve the hypothalamic-pituitary-adrenal axis and metabolic changes that occur as a result of chronic anxiety or stress. Taking into account evidence from studies conducted in the general population, veterans who are overweight or obese are likely to be at increased risk for adult-onset chronic diseases such as coronary heart disease, diabetes, hypertension, arthritis, and several forms of cancer [6
]. Long-term follow up studies of the persistence of PTSD, CFS-like illness, and unexplained MSI, among Gulf War veterans must be conducted in the context of changing risks of chronic diseases that occur among both veteran and non-veteran populations as people get older. Although reverse causation is often an important consideration in studies of comorbid health conditions, all of the men and women included in the current study had to have been physically fit at the time they entered military service. The military has weight limits based upon height, weight, and sex. Each branch of the military has its own body composition standards. Persons with certain health conditions are excluded from military service. Military service itself is often physically demanding. As a result, veteran populations such as those who served in the 1991 Gulf War are not comparable to persons in the general population. The current study provides important new information about comorbidity between obesity or overweight and other important veterans health concerns such as PTSD, CFS-like illness, and unexplained MSI. Although there was some indication that BMI modified the effect of CFS-like illness on PTSD, obesity was an important comorbid health condition among both deployed and nondeployed veterans with CFS-like illness or PTSD.
The troops who served in the 1991 Gulf War were exposed to many stressors including rapid mobilization, wartime hostilities, and concerns about potential chemical attacks. These and other war-time exposures (for example, witnessing deaths or being exposed to hostile fire) may have led to PTSD among some of these veterans). PTSD may lead to other adverse health outcomes and conditions. In previous studies, PTSD has been associated with obesity, metabolic syndrome, and other CHD risk factors in veterans [13
]. In the current study, PTSD was positively associated with obesity after adjustment for age, sex, Gulf status, and other factors. Although the direction of the association cannot be determined from this cross-sectional analysis of data from the 2003–2005 follow-up survey, it is possible that veterans with PTSD are more likely to consume a high caloric diet or less likely to exercise. This is speculative, however, since the current study lacked data on diet or physical activity.
With respect to other limitations of the current study, exposures such as body mass index and weight were based upon self-reported information. However, studies conducted in non-veteran populations have suggested that the reliability and validity of self-reported information about height and weight obtained in large-scale epidemiologic studies are reasonably good [24
]. Estimates of BMI obtained from self-reported information are more accurate among persons less than 55 years of age than those 55 or older and may also vary by gender and ethnicity [25
]. A further issue is that estimates of weight may be preferable to BMI for assessing over-weight since weight-for-height indices may not adequately distinguish between adipose individuals and those who are heavily muscled [1
]. Response bias is also a possibility in view of the response rate of 34%. In a previous analysis of these data, Kang et al
] compared characteristics of respondents and nonrespondents, stratified by Gulf deployment status. In both Gulf War veteran and Gulf Era veteran groups, nonrespondents were more likely to be younger, non-white individuals who served in enlisted ranks at the time of the 1991 Gulf War. In addition, Gulf War veteran participants were more likely women and on National Guard or reserve during the Gulf War service than Gulf War veteran nonparticipants [18
In conclusion, overweight and obesity are highly prevalent among Gulf War and Gulf Era veterans. These veterans are likely to be at increased risk of chronic diseases associated with overweight and obesity. Consideration of war-related health conditions such as PTSD should take into account not only war time traumatic experiences and other exposures but also the fact that people have a higher risk of chronic conditions (for example, diabetes, cardiovascular disease, and arthritis) as they get older. Gulf War and Gulf Era veterans who are obese are more likely to have certain chronic health conditions including PTSD. Additional studies are needed of comorbidity between obesity and Gulf War illnesses such as CFS-like illness, unexplained MSI, and PTSD.